1. Field of the Invention
The present invention broadly relates to a deposition apparatus.
2. Description of the Related Art
The direct current sputtering apparatus is known as a type of deposition apparatus.
FIG. 5 is a cross sectional view of a direct current sputtering apparatus, in which reference numeral 501 denotes a deposition chamber, reference numeral 502 denotes a substrate, reference numeral 503 denotes a supporting member, reference numeral 504 denotes an exhaust tube, reference numeral 505 denotes a target electrode, reference numeral 506 denotes a magnet for generating a magnetron magnetic field, reference numeral 507 denotes a gas-introducing tube, and reference numeral 508 denotes a direct current power supply.
The pressure in the deposition chamber 501 is reduced down to 10.sup.-6 Torr through an exhaust system (not shown). Then, gas is introduced into the deposition chamber 501 from the gas-introducing tube 507, so as to keep the pressure in the deposition chamber 501 at a predetermined value. Thereafter, voltage is applied to the target 505 from the direct current power supply 508 to generate plasma which strikes the target, whereby a film accumulates on the surface of the substrate 502.
The above-described conventional deposition apparatus, however, has a problem in that the target cannot be used with high efficiency because of erosion of the target caused by a magnetron magnetic field.
In addition, since the ions cannot be maintained at a high density and low energy, it is difficult to achieve deposition of a highly-crystalline, polycrystalline Si, or MgF.sub.2 having a low absorption of light.
Accordingly, an object of the present invention is to provide a deposition apparatus which overcomes the prior art problems, allows the target to be used efficiently, and maintains the ions at a high density and low energy.